Synthesis and Antitubercular Activity of 2‐(substituted phenyl/benzyl‐amino)‐6‐(4‐chlorophenyl)‐5‐(methoxycarbonyl)‐4‐methyl‐3,6‐dihydropyrimidin‐1‐ium Chlorides

A series of 2‐(substituted phenyl/benzyl‐amino)‐6‐(4‐chlorophenyl)‐5‐(methoxycarbonyl)‐4‐methyl‐3,6‐dihydropyrimidin‐1‐ium chlorides 7–13 and 15 was synthesized in their hydrochloride salt form. The title compounds were characterized by FT‐IR, NMR (¹H and ¹³C) and elemental analysis. They were evaluated for their in vitro antitubercular activity against Mycobacterium tuberculosis H37Rv, multidrug resistance tuberculosis and extensively drug resistance tuberculosis by agar diffusion method and tested for the cytotoxic action on peripheral blood mononuclear cells by MTT assay. Among all the tested compounds in the series, compounds 7 and 11 emerged as promising antitubercular agents at 16 μg/mL against multidrug resistance tuberculosis and over 64 μg/mL against extensively drug resistance tuberculosis. The conformational features and supramolecular assembly of the promising compounds 7 and 11 were determined by single crystal X‐ray study.     

Effect of dimethylnitrosamine‐induced liver dysfunction on the pharmacokinetics of 5‐fluorouracil after administration of S‐1, an antitumour drug,to rats

Objectives The anti‐tumour agent S‐1 comprises tegafur (a prodrug of 5‐fluorouracil; 5‐FU), gimeracil (2‐chloro‐2,4‐dihydroxypyridine (CDHP); a competitive inhibitor of 5‐FU metabolism) and oteracil potassium. The effect of hepatic dysfunction induced by dimethylnitrosamine (DMN) on the pharmacokinetics of 5‐FU after administration of S‐1 to rats was investigated. Methods S‐1 (5 mg/kg) was administered intravenously and orally to rats with DMN‐induced liver dysfunction. Plasma concentrations of S‐1 components and 5‐FU were measured by HPLC and LC/MS‐MS. Blood tests and in‐vitro enzymatic investigations were also conducted. Key findings DMN treatment induced hepatic dysfunction and decreased the conversion of tegafur to 5‐FU in the liver without altering renal function or dihydropyrimidine dehydrogenase activity. Following intravenous administration of S‐1, the blood concentration‐time profiles of CDHP were similar between control rats and rats with hepatic dysfunction, but the half‐life of tegafur was significantly prolonged. The maximum plasma concentration (C_max) of 5‐FU was significantly reduced and the area under the blood concentration‐time curve (AUC) was reduced by 22%. Following oral administration, the C_max of tegafur, 5‐FU and CDHP were significantly decreased and half‐lives significantly increased. Hepatic dysfunction had a less pronounced effect on the AUC of 5‐FU (13.6% reduction). Conclusions The pharmacokinetic profiles of tegafur, 5‐FU and CDHP were altered by changes in the elimination rate of tegafur induced by a decrease in the conversion of tegafur to 5‐FU. However, hepatic dysfunction had less of an effect on the AUC of 5‐FU, which correlates with anti‐tumour effect, after the oral administration of S‐1.     

Biochemical modulation of 5-fluorouacil through dihydropyrimidine dehydrogenase inhibition: a Southwest Oncology Group phase II trial of eniluracil and 5-fluorouracil in advanced resistant colorectal cancer

Purpose. To investigate thehypothesis that a systemic agent designedto inhibit dihydropyrimidine dehydrogenase(DPD), the first enzyme in thefluoropyrimidine degradative pathway, couldimprove the effective amount of5-fluorouracil (5-FU) delivered to a tumorresulting in enhanced response. Patients and methods. Eligibility includedcytologically or pathologically verifieddiagnosis of colorectal cancer thatrecurred during or within 12 months ofcompletion of adjuvant therapy,representing patients generally consideredresistant to fluorinated pyrimidinetherapy. Stratification was into twocohorts: recurrence while receivingadjuvant therapy, and relapse within 12months of completing adjuvant therapy.Treatment consisted of 28 days of oraltherapy every five weeks with eniluraciland 5-FU administered in a 10:1 ratio. Thedaily dose of eniluracil was 10 mg/m²with 5-FU 1 mg/m², divided into twodoses. Results. Twenty-five patientsare evaluable for response: 9 relapsedduring therapy and 16 relapsed within oneyear of adjuvant therapy. In the firstgroup, there was one partial response (9%;95% CI 0–41%); in the second cohort therewas one confirmed complete response (5%;95% CI 0–23%) and one unconfirmed partialresponse, for an overall response rate of10%. Conclusions. This regimen lackssignificant activity in this targetpopulation. Pre-treatment intratumoral DPDexpression was not assessed, therefore themechanism of fluorinated pyrimidineresistance cannot be specificallyattributed to elevated DPD levels.Attempting restoration of chemotherapysensitivity through blockade of enzymes orsignal transduction molecules responsiblefor resistance is rational, provided thattumor target expression is the basis fortrial entry.     

Combined 5‐hydroxymethylcytosine content of human leucocyte antigen‐B and human leucocyte antigen‐DQB1 as novel biomarker for anti‐tuberculosis drug‐induced liver injury

This study investigated the diagnostic value of 5‐methylcytosine (5‐mC) and 5‐hydroxymethylcytosine (5‐hmC) contents of human leucocyte antigen (HLA)‐B and HLA‐DQB1 in anti‐tuberculosis drug‐induced liver injury (ADLI). In total, 110 ADLI patients and 120 patients without ADLI controls were enrolled. Enzyme‐linked immunosorbent assay (ELISA) was used to detect the 5‐mC and 5‐hmC content in DNA from peripheral blood leucocytes. The univariate analysis showed that smoking, drinking, and 5‐mC and 5‐hmC content of HLA‐B and HLA‐DQB1 were significantly associated with ADLI. After adjusting for drinking and smoking, we found that 5‐mC content of HLA‐B and HLA‐DQB1 were associated with ADLI (odds ratio [OR] = 0.251 and 0.347, respectively) and 5‐hmC contents of HLA‐B and HLA‐DQB1 were also associated with ADLI (OR = 1.848 and 4.705, respectively). Receiver operating characteristic (ROC) analysis indicated that the 5‐hmC contents of both HLA‐B and HLA‐DQB1 were more clinically significant than the 5‐mC contents were. The combined 5‐hmC level of HLA‐B and HLA‐DQB1 was the best diagnostic biomarker for ADLI, with the highest areas under the curve (AUC) for 0.953, sensitivity for 0.900 and specificity for 0.875. Therefore, combined 5‐hmC levels of HLA‐B and HLA‐DQB1 could be significant evidence for diagnosis of ADLI.     

Population pharmacokinetics of the 11β‐hydroxysteroid dehydrogenase type 1 inhibitor ABT‐384 in healthy volunteers following single and multiple dose regimens

ABT‐384 is a potent and selective inhibitor of 11β‐hydroxysteroid dehydrogenase type 1 (HSD‐1). The pharmacokinetics of ABT‐384 was evaluated in healthy volunteers in single‐dose (1, 8, 20, 50, 120 and 240 mg) and multiple‐dose studies (1, 2, 4, 8, 20, 30 and 100 mg once daily). Less than dose‐proportional pharmacokinetics of ABT‐384 was observed when ABT‐384 was administered at single doses lower than 8 mg. This nonlinear phenomenon disappeared after repeated doses. The dose‐normalized plasma concentration–time curves superposed across all dose groups on day 7, but not on day 1. This phenomenon cannot be explained by the half‐life of ABT‐384. Based on available data, the nonlinearity is likely due to binding of ABT‐384 to a high‐affinity‐low‐capacity site, such that this interaction was reflected in ABT‐384 pharmacokinetics. To characterize the pharmacokinetics of ABT‐384, a population pharmacokinetic model for ABT‐384 was constructed. The model provided reasonable fitting for both single‐ and multiple‐dose data. Further investigation is warranted to evaluate the disposition of ABT‐384 at low doses using a larger number of subjects. The constructed model would be useful in predicting ABT‐384 concentrations at different doses and guiding the selection of dosing regimens in further clinical trials. Copyright © 2014 John Wiley & Sons, Ltd.     

A physiologically based pharmacokinetic (PBPK) approach to evaluate pharmacokinetics in patients with cancer

Potential differences in pharmacokinetics (PK) between healthy subjects and patients with cancer were investigated using a physiologically based pharmacokinetic approach integrating demographic and physiological data from patients with cancer. Demographic data such as age, sex and body weight, and clinical laboratory measurements such as albumin, alpha‐1 acid glycoprotein (AAG) and hematocrit were collected in ~2500 patients with cancer. A custom oncology population profile was built using the observed relationships among demographic variables and laboratory measurements in Simcyp® software, a population based ADME simulator. Patients with cancer were older compared with the age distribution in a built‐in healthy volunteer profile in Simcyp. Hematocrit and albumin levels were lower and AAG levels were higher in patients with cancer. The custom population profile was used to investigate the disease effect on the pharmacokinetics of two probe substrates, saquinavir and midazolam. Higher saquinavir exposure was predicted in patients relative to healthy subjects, which was explained by the altered drug binding due to elevated AAG levels in patients with cancer. Consistent with historical clinical data, similar midazolam exposure was predicted in patients and healthy subjects, supporting the hypothesis that the CYP3A activity is not altered in patients with cancer. These results suggest that the custom oncology population profile is a promising tool for the prediction of PK in patients with cancer. Further evaluation and extension of this population profile with more compounds and more data will be needed. Copyright © 2012 John Wiley & Sons, Ltd.     

Anticancer activity using positron emission tomography‐computed tomography and pharmacokinetics of β‐eudesmol in human cholangiocarcinoma xenografted nude mouse model

Cholangiocarcinoma (CCA) is an important public health problem in several parts of South East Asia, particularly in Thailand. The limited availability of effective diagnostic tools for early stage CCA, including chemotherapeutic options, constitutes a major problem for treatment and control of CCA. The aim of the present study was to assess the anti‐CCA activity and pharmacokinetics of β‐eudesmol in CCA‐xenografted nude mouse model and healthy mice. Positron emission tomography‐computed tomography (PET‐CT) with ¹⁸F‐fluorodeoxyglucose was used for detecting and monitoring tumour development, and PET‐CT with technetium‐99m was used to investigate its pharmacokinetics property. Results support the role of PET‐CT as a potential tool for detecting and monitoring the progress of lung metastasis. Tumour size and lung metastasis were significantly inhibited by 91.6% (of baseline) and 95% (of total lung mass), respectively, following treatment with high‐dose β‐eudesmol (100 mg/kg body weight for 30 days). Survival time was prolonged by 64.4% compared with untreated controls. Systemic clearance of the compound was rapid, particularly during the first 60 min. The compound was distributed to the vital organs at maximum levels 2 h after oral administration and 15 min after intravenous injection. Results from the present study suggest the potential of β‐eudesmol as a promising candidate for further development as an anti‐CCA drug with respect to its pharmacodynamics and pharmacokinetic properties. PET‐CT, with radiotracers ¹⁸F‐fluorodeoxyglucose and technetium‐99m, was shown to be a reliable tool in the investigation of anti‐CCA and pharmacokinetic properties of β‐eudesmol in CCA‐xenografted and healthy mice.     

MicroRNA‐33a‐5p suppresses colorectal cancer cell growth by inhibiting MTHFD2

Colorectal cancer (CRC) is one of the most common malignancies with high levels of invasiveness, drug resistance and mortality, but the internal mechanisms of CRC are largely unknown. MicroRNAs (miRs) have been reported to be involved in the development of CRC, and numerous studies have demonstrated that the abnormal expression of miR‐33a‐5p might be associated with CRC. However, the function and downstream mechanism of miR‐33a‐5p in colorectal cancer (CRC) remains unclear. Methylenetetrahydrofolate dehydrogenase 2 (MTHFD2), a mitochondrial enzyme involved in folic acid metabolism, interestingly was confirmed to be one of the target genes of miR‐33a‐5p in the present study. We first confirmed that miR‐33a‐5p in CRC tissues and cell lines were downregulated (P < 0.05), and that the proliferation, clone formation capacities, G1/S progression, and migration capacities of the two CRC cell lines HCT116 cells and HT29 were suppressed by miR‐33a‐5p overexpression in vitro (P < 0.05). Ctrl HCT116 and miR‐33a‐5p‐overexpressing HCT116 were injected into nude mice. In vivo tumour formation was significantly suppressed by miR‐33a‐5p overexpression (P < 0.05) as well as the proliferation marker Ki67 (P < 0.05). Additionally, MTHFD2 protein expression was significantly enhanced in CRC tissues. From bioinformatics predictions and a luciferase report analysis, MTHFD2 was confirmed to be one of the target genes of miR‐33a‐5p. In contrast to the role of miR‐33a‐5p overexpression, MTHFD2 overexpression promoted the proliferation and migration of HCT116 and HT29 cells (P < 0.05), which confirmed that MTHFD2 was a functional target gene of miR‐33a‐5p. In conclusion, miR‐33a‐5p inhibits the growth and migration of CRC by targeting MTHFD2.     

Role of osteopontin as a predictive biomarker for anti-EGFR therapy in triple-negative breast cancer

Objective: Effective targeted therapies for patients with triple-negative breast cancer (TNBC) present an unmet clinical need. There is evidence that TNBCs often have increased expression of the epidermal growth factor receptor (EGFR) and of osteopontin (OPN). OPN-mediated signaling can activate EGFR-dependent signaling pathways. Here, we assessed OPN as a potential predictive biomarker for response to anti-EGFR therapy in TNBC.

Research design and methods: Using two different TNBC cell lines, MDA-MB-468 and MDA-MB-231, we investigated the impact of stable expression of OPN on efficacy of the EGFR inhibitor erlotinib in vitro.

Results: We observed that breast cancer cells engineered to overexpress OPN are more sensitive to growth inhibition by erlotinib than control cells. The level of response was related to the level of OPN expression, possibly due to increased phosphorylation status of EGFR Tyr1068.

Conclusions: These results indicate that OPN expression levels are related to sensitivity of TNBC cells to growth inhibition by erlotinib. OPN thus is a promising predictive biomarker for anti-EGFR therapy in breast cancer.     

Effect of acute hepatic failure on the hepatic first‐pass effect of 5‐fluorouracil in rats

Objectives In cancer chemotherapy for hepatocellular carcinoma, 5‐fluorouracil is widely used and has typically been given by intrahepatic arterial (i.a.) infusion to increase treatment efficacy and reduce systemic toxicity. 5‐Fluorouracil is eliminated primarily by the liver and so the hepatic first‐pass effect after intrahepatic arterial administration of 5‐fluorouracil may be lower in patients with hepatic failure, and systemic toxicity may not be reduced. In this study, we have investigated the effect of acute hepatic failure on the first‐pass effect of 5‐fluorouracil in rats. Methods Experimental acute hepatic failure was induced by treatment with carbon tetrachloride (CCl₄). 5‐Fluorouracil was infused for 15 min into the hepatic artery or the saphenous vein of rats at a dose of 1.25 mg/kg. Key findings Hepatic availability in 50% CCl₄‐treated (severe hepatic failure) rats was higher than in controls. Conclusions The hepatic first‐pass effect after intrahepatic arterial administration of 5‐fluorouracil was lower in severe hepatic failure. Therefore, the reducing effect of the systemic toxicity after intrahepatic arterial administration may be lower in severe hepatic failure.     

Radiolabeling and in vitro evaluation of a new 5‐fluorouracil derivative with cell culture studies

The clinical impact and accessibility of ^99mTc tracers for cancer diagnosis would be greatly enhanced by the availability of a new, simple, and easy labeling process and radiopharmaceuticals. 5‐Fluorouracil is an antitumor drug, which has played an important role for the treatment of breast carcinoma. In the present study, a new derivative of 5‐Fluorouracil was synthesized as (1‐[{1′‐(1′′‐deoxy‐2′′,3′′:4′′,5′′‐di‐O‐isopropylidene‐β‐D‐fructopyranose‐1′′‐yl)‐1′H‐1′,2′, 3′‐triazol‐4′‐yl}methyl]‐5‐fluorouracil) ( E ) and radiolabeled with ^99mTc. It was analyzed by radio thin layer chromatography for quality control and stability. The radiolabeled complex was subjected to in vitro cell‐binding studies to determine healthy and cancer cell affinity using HaCaT and MCF‐7 cells, respectively. In addition, in vitro cytotoxicity studies of compound E were performed with HaCaT and MCF‐5 cells. The radiochemical purity of the [^99mTc]Tc E was found to be higher than 90% at room temperature up to 6 hours. The radiolabeled complex showed higher specific binding to MCF‐7 cells than HaCaT cells. IC₅₀ values of E were found 31.5 ± 3.4 μM and 20.7 ± 2.77 μM for MCF‐7 and HaCaT cells, respectively. The results demonstrated the potential of a new radiolabeled E with ^99mTc has selective for breast cancer cells.     

Syntheses of [14C]‐labeled 2‐(3‐chlorophenyloxy)‐3‐[3‐(3‐hydroxy) pyridin‐4‐yl propoxy]pyridine,a phosphodiesterase 4 inhibitor and its metabolites

We describe here the synthesis of [¹⁴C]‐2‐(3‐chlorophenyloxy)‐3‐[3‐(3‐hydroxy)pyridin‐4‐yl propoxy]pyridine (1), a phosphodiesterase 4 inhibitor. [¹⁴C]‐Labeled 1 was prepared in three steps from [¹⁴C]‐2‐bromopyridin‐3‐ol in an overall yield of 32%. Preparation of [¹⁴C]‐labeled 2 and 3, two metabolites of 1, is also described. Copyright © 2014 John Wiley & Sons, Ltd.     

Virtual screening,SAR, and discovery of 5‐(indole‐3‐yl)‐2‐[(2‐nitrophenyl)amino] [1,3,4]‐oxadiazole as a novel Bcl‐2 inhibitor

A new series of oxadiazoles were designed to act as inhibitors of the anti‐apoptotic Bcl‐2 protein. Virtual screening led to the discovery of new hits that interact with Bcl‐2 at the BH3 binding pocket. Further study of the structure–activity relationship of the most active compound of the first series, compound 1 , led to the discovery of a novel oxadiazole analogue, compound 16j , that was a more potent small‐molecule inhibitor of Bcl‐2. 16j had good in vitro inhibitory activity with submicromolar IC₅₀ values in a metastatic human breast cancer cell line (MDA‐MB‐231) and a human cervical cancer cell line (HeLa). The antitumour effect of 16j is concomitant with its ability to bind to Bcl‐2 protein as shown by an enzyme‐linked immunosorbent assay (IC₅₀ = 4.27 μm ). Compound 16j has a great potential to develop into highly active anticancer agent.     

Association between the pharmacokinetics of capecitabine and the plasma dihydrouracil to uracil ratio in rat: A surrogate biomarker for dihydropyrimidine dehydrogenase activity

Capecitabine is a 5‐fluorouracil (5‐FU) derivative that is used widely in the treatment of colorectal cancer. The plasma ratio of dihydrouracil (UH₂) to uracil (Ura) is expected to gain relevance as an indirect‐response biomarker to estimate the activity of dihydropyrimidine dehydrogenase (DPD). The latter is a rate‐limiting enzyme in the catabolism of 5‐FU in the capecitabine‐based regimen. However, the relationship between the pharmacokinetics of capecitabine and the plasma UH₂/Ura ratio is still unknown. This study evaluated the time‐course alterations of the plasma UH₂/Ura ratio in rats treated with 180 mg/kg capecitabine. The molar ratio tended to increase within 1.5 h (1.85 ± 0.76 at 1.5 h after administration of capecitabine) and gradually recovered to its initial level (1.00 ± 0.46). The results of the current study suggest that the plasma UH₂/Ura ratio temporarily increases following administration of capecitabine, possibly related to the DPD activity levels. The plasma UH₂/Ura ratio might assist in monitoring the alteration of DPD activity levels in capecitabine treatments.     

Comparison of crossover and parallel‐group designs for the identification of a binary predictive biomarker of the treatment effect

Pros and cons of crossover design are well known for estimating the treatment effect compared to parallel‐group design, but remain unclear for identifying and estimating an interaction between a potential biomarker and the treatment effect. Such ‘predictive’ biomarkers, or ‘effect modifiers’, help to predict the response to specific treatments. The purpose of this report was to better characterize the advantages and disadvantages of crossover versus parallel‐group design to identify predictive biomarkers. The treatment effect, the effect of a binary biomarker and their interaction were modelled using a linear model. The intra‐subject correlation in the crossover design was taken into account through an intra‐class correlation coefficient. The variance‐covariance matrix of the parameters was derived and compared. For both trial designs, the variance of the parameter estimating an interaction between the treatment effect and a potential predictive biomarker corresponds to the variance of the parameter estimating the treatment effect, multiplied by the inverse of the frequency of the candidate biomarker. The ratio of the variance of the interaction parameter in the crossover to the variance estimated in the parallel‐group design depends on the complement of the intra‐class correlation coefficient. When planning a clinical trial including a search for candidate biomarker, the frequency of the candidate biomarker helps design the sample size, and the intra‐subject correlation of the outcome should be taken into account for choosing between parallel‐group and crossover designs.     

Plasma miR‐208 as a useful biomarker for drug‐induced cardiotoxicity in rats

Cardiotoxicity is one of the major safety concerns in drug development. Therefore, detecting and monitoring cardiotoxicity throughout preclinical and clinical studies is important for pharmaceutical companies. The present study was conducted in order to explore a plasma miRNA biomarker for cardiotoxicity in rats. As organ specificity is an important factor for a biomarker, we analyzed the miRNA microarray dataset in 55 organs/tissues in normal male rats. Based on this analysis, 5 miRNAs consisting of miR‐208 (heart‐specific), miR‐1, miR‐133a, miR‐133b (heart and skeletal muscle‐specific) and miR‐206 (skeletal muscle‐specific) were selected. Next, we evaluated the usefulness of those 5 miRNAs as circulating biomarkers in rats administered with single‐dose isoproterenol or doxorubicin. Plasma miR‐208 was consistently increased through 24 h after dosing in rats administered with isoproterenol, whereas plasma concentrations of cardiac troponin (cTn) showed transient elevation. In contrast, the plasma levels of miR‐1, miR‐133a, miR‐133a and miR‐206 were elevated after treatment with doxorubicin, probably as a result of skeletal muscle toxicity. Additionally, the plasma miR‐208 level was elevated even after repeat‐dose administration (once daily for 7 days) of isoproterenol under which the pathological condition proceeded to the sub‐chronic phase such as fibrosis. Thus, our data suggest that miR‐208 is a promising plasma biomarker for cardiotoxicity in rats. Monitoring of plasma miR‐208 levels in rats may lead to more accurate evaluation of cardiotoxicity in preclinical studies. Copyright © 2014 John Wiley & Sons, Ltd.